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Mypy ignore_missing_imports in Pyrefly

website/docs/migrate/mypy/ignore-missing-imports.mdx

1.3.0-dev.23.3 KB
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Mypy's ignore_missing_imports suppresses errors when an imported module cannot be resolved. In a per-module override the pattern matches the imported module, not the file that contains the import. Pyrefly's equivalent works the same way.

Mypy configuration

toml
[tool.mypy]

[[tool.mypy.overrides]]
module = ["optional_vendor.*"]
ignore_missing_imports = true

Pyrefly equivalent

toml
ignore-missing-imports = ["optional_vendor.*"]

pyrefly init converts both per-module and global mypy import suppression into this list. A global ignore_missing_imports = true becomes the module glob "*".

Do not confuse the two Pyrefly settings

SettingBehavior
ignore-missing-importsSubstitutes Any only when the matched module cannot be found. If it is found, its real type information is used.
replace-imports-with-anyAlways substitutes Any for the matched module, even when source or stubs are available.
[errors] missing-import = "ignore"Suppresses missing-import diagnostics everywhere, rather than for selected modules.

Prefer ignore-missing-imports for optional dependencies. replace-imports-with-any is the closer match for mypy's follow_imports = "skip", and it is a much stronger escape hatch.

:::warning

pyrefly init currently groups follow_imports = "skip" with ignore_missing_imports, so a migrated skip rule lands in ignore-missing-imports and keeps type information for modules that do resolve. Inspect the generated list and move entries to replace-imports-with-any where you need mypy's unconditional skip behavior.

:::

Diagnose before suppressing

An unresolved import is often a misconfigured environment rather than a missing dependency. Check that:

  1. the dependency is installed in the interpreter Pyrefly queries;
  2. python-interpreter-path selects the intended environment;
  3. your source roots are listed in search-path;
  4. custom stubs live in site-package-path;
  5. the module name matches the package layout.

If the module resolves from the command line but not in the IDE, or the other way round, the two are using different configs or different interpreters.

Example migration

Mypy:

ini
[mypy]
mypy_path = src

[mypy-vendor_sdk.*]
ignore_missing_imports = True

Pyrefly:

toml
search-path = ["src"]
ignore-missing-imports = ["vendor_sdk.*"]

Pyrefly supports mypy's module name pattern syntax; see Module Globbing for the exact matching rules.